Development of a mass production process for fibre-reinforced parts with transparent polyurethane matrix exemplarily for a CFRP seat back with a visible surface

• Applicant: Professor Dr.-Ing. Christian Hopmann
• Subject Area: Plastics Engineering
• Term: from 2015 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 266002500

High performance parts made from composites and polyurethane (PU) as matrix material have proven their economic potential in many industrial applications. However, the disadvantages of the produced parts are the low fibre volume content and the use of foamed PU, which leads to a limited mechanical performance. The development in the field of PU spray impregnation of continuous fibre textiles (Resin Spray Prepregging (RSP)) in combination with an optimised forming and curing process within the research unit (FOR860) allows the automated production of high performance parts in short cycle times with a high fibre volume content (> 50 %).The scientific focus of the FOR860 was the development of the production technology and the achievable mechanical properties. For specific applications, further requirements regarding the surface of the parts are requested. The aim of this transfer project is to transfer the knowledge of the projects 4 and 8 of the FOR860 to the manufacturing of highly loadable parts with a defined surface quality and to generate detailed process knowledge. The textile reinforcement should be visible without drawing its structure on the surface in order to reduce the refinishing operations. For an implementation of the production technology, there are further scientific investigations necessary. Because of the complexity, these investigations are only feasible by interdisciplinary cooperation between industrial companies and a research institute. Within the investigations of the FOR860, it could be shown, that by an adapted process and machine technology the manufacturing of almost pore-free monolithic parts is possible. To enable this technology for the manufacturing of parts with defined surface properties, systematic investigations on test specimens will be made to determine the influence of the raw materials binder, fabrics and PU-systems on the mechanical properties at various temperatures. Following that, the manufacturing of fibre-reinforced plastic parts is analysed using two parallel research approaches. The investigation will include a variation of the process, material and preforming parameters as well as an adaption of the tooling technology. To be consistent with the industrial requirements, the surface properties will be tested by different environmental conditions (alternating climate test, UV radiation) in defined times. The fundamental research on planar parts will be followed by the transfer of the knowledge to a seat back in lightweight design. The chosen geometry of the seat shall enable the knowledge transfer to other structural components

• DFG Programme: Research Grants (Transfer Project)
• Application Partner: BMW AG; Werk Dingolfing; Mubea Carbo Tech GmbH
• Co-Investigators: Dr.-Ing. Roman Bouffier; Dr.-Ing. Kai Fischer